RU2557781C2 - Device for electrodes fixation - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: group of inventions relates to medical equipment. The device contains an external layer, connected to an internal layer, from which it is partially separated by a middle layer. The external layer consists of a rigid material, impermeable for a flowing medium. The internal layer is made from an elastic material, impermeable for the flowing medium and having regions for the placement of sensors or electrodes, and is directly connected to the external layer on its perimeter. The middle layer contains the flowing medium and is made with a possibility of pumping the flowing medium from it to provide the uniform stretching of the internal layer, increase of the distance between the electrodes and their placement irrespective of the patient's head size. The device contains means for the regulation of the flowing medium pressure in the middle layer. Disclosed is the application of the device for the registration of an electroencephalogram and a method of placing the electrodes on the head skin.

EFFECT: inventions solve the problem of convenience improvement.

12 cl, 6 dwg

Description

FIELD OF THE INVENTION

The invention relates to a device and a method for placing and fixing sensors / electrodes on a patient’s head.

State of the art

In Europe and Russia, for reasons of a historical nature, measurements of the electrical activity of the brain have found particularly wide application in neurophysiological and psychophysiological diagnostics. Since the 1960s, a significant part of the developments related to the interpretation of biological feedback has been carried out in the USA, Canada, Australia, Europe and Russia. Specialists in this field know both biological and technical methods for measuring various types of brain activity and effects on these types. The most common methods include electroencephalography (EEG), hemoencephalography (GEG) and magnetoencephalography (MEG). In the framework of quantitative EEG measurements (CEEG), several mathematical models have been developed that allow to measure discriminant (recognition) functions, such as coherence (synchronization), phase, ratio of statistics before and after processing according to the methodology of the International Family Therapy Association (IFTA), low frequency , the ratio of the coherent phase at the moment with Z-scores of biological feedback and other patterns.

KEEG is carried out in the same way as conventional EEG recording, i.e. the operator places several (21+) electrodes on the patient’s head in order to simultaneously register most of the electrical activity of the brain. This activity is recorded over a period of time, and it is possible to add functional assignments that go beyond the standard set, such as measurements with open and closed eyes. The information received is often correlated with activity, which is analyzed by all the various software systems installed by the operator. Some of these programs use various mathematical models for the diagnosis, while others use system models (the so-called protocols) for interpretation. Among other factors, the crucial point is the installation of electrodes in the CEEG system in the right way, with good contact between the electrodes and the scalp. This is important for obtaining the optimal basis used when comparing two measurements or when comparing measurements taken for two or more people. Therefore, in a standard embodiment, the electrodes are placed according to the accepted international system 10-20, described, for example, in the publication Erns Niedermeyer, Fernando Lopes da Silva: Electroencephalography: Basic Principles, Clinical Applications and Related Fields, p.140. The task of obtaining the same result through two different measurements is very difficult; therefore, for the further development of science and, in particular, research in this area, it is highly desirable to have a system more standardized in comparison with all known systems.

Currently, most EEG and CEEG systems basically use an elastic mesh and / or helmet made in accordance with a 10-20 system or other less common placement patterns. Such helmets are made in various designs with holes for introducing electrodes. In addition, helmets have different sizes, as the distance between the electrodes should correspond to the size of the skull, taken into account in the system 10-20 or in other layouts. Often the problem is that helmets cannot provide sufficient electrode pressure to the skull due to its shape and the presence of hair. Tight helmets usually cause inconvenience to the patient, especially children who are more sensitive.

To obtain a signal without too much noise background, it is necessary to optimize the measurement process, since such noise will lead to less accurate measurements and, accordingly, to less accurate information. The electrodes must be manually installed in the correct way, taking into account the varying sizes of the skull, and this task often requires time and staff competence. In addition, with such manual placement of the electrodes, the probability of their improper installation due to the human factor increases.

In patent application US 2007/0106170 A1, a helmet with electrodes / sensors is described for use in an EEG. To supply pressure to the electrodes used many inflatable chambers. Such a technical solution, i.e. the use of inflatable chambers according to this application requires several helmets made in accordance with the individual dimensions of the skull, moreover, when placing the electrodes, manual adjustment is also necessary.

SU 676273 A1 also describes a helmet with electrodes / sensors for use in EEGs. The technical solution that provides adequate pressure to the electrodes is approximately the same as in the application US 2007/0106170 A1. In this case, the inflatable chambers are formed by attaching the inner layer of the helmet to the outer shell / outer layer so that each electrode forms its own separate inflatable chamber. The disadvantages of this technical solution are the same as for the application US 2007/0106170 A1.

Patent Application JP 2006-6667 And also presents a helmet with electrodes / sensors, intended for use in EEG. In one embodiment, in order to apply pressure to the electrodes located on the internal component of the helmet, chambers are inflated, which are separated from each other and are located between the internal and external components of the helmet. In this case, the helmet has the same disadvantages as the helmet according to US 2007/0106170 A1.

In addition to neurophysiological / psychophysiological diagnostics and treatment courses, measurements of brain electrical activity are also used in several other areas. In the field of biotechnology, using such measurements, it is possible to transform, using appropriate sensors, the electrical impulses emanating from the brain into electronic signals, which can then be used to control various technical control systems. Such systems may include, for example, fighter pilot helmets, speech synthesizers, robots, various entertainment devices such as computer games, as well as other systems using brain-computer interaction.

Disclosure of invention

The problem to which the present invention is directed, is to develop a method and device for arranging and securing sensors / electrodes on a person’s head. The proposed device / method optimizes the information contained in the recorded signals, and avoids some of the problems inherent in known devices and methods.

The device, its use and the method according to the invention are characterized in the attached formula.

This device can replace the currently known helmets. The device has an internal helmet / layer made of an elastic material that is impervious to the fluid. The impermeable component is attached directly to the outer hard layer / shell, which allows uniform expansion of the inner helmet / layer. Between the outer shell and the inner helmet is located the middle layer, which contains a fluid and / or material capable of compressing / expanding uniformly depending on the gas pressure or the amount of fluid. An elastic helmet / layer has dimensions slightly smaller than the smallest of the heads to which it will fit, since in order to obtain an optimal signal, the inner layer must be able to apply pressure directed to the skull to the EEG electrodes. A gas or liquid pump, by removing fluid from the middle layer, provides a reduced pressure / vacuum between the rigid outer shell and the inner elastic helmet. As a result, the elastic helmet expands uniformly, acquiring larger sizes compared to the patient’s head. The patient then puts on a helmet, and the fluid is returned to the middle layer using pressure adjusting means such as a valve. As a result, the inner layer is compressed and provides pressure to the electrodes, pressing them to the skull. In addition, due to the uniform expansion of the elastic helmet, the distance between the electrodes increases uniformly. When using, for example, system 10-20, this helmet device allows you to properly adjust the distance between the electrodes, and regardless of the size of the patient’s head. It provides more economical spending of time and resources, as well as an increased level of standardization of the system for KEG analysis. In addition to the above, there is no need to spend time on individual adaptation and have a large number of helmets with different sizes and with the possibility of choice for each patient.

The present invention was developed mainly for use in conjunction with EEG sensors, but this is not limited to this, since without any other conditions it can be adapted for use with MEG sensors and GEG sensors, as well as with other sensors, intended for use in measuring brain activity.

Brief Description of the Drawings

Figure 1 in cross section illustrates the device according to the invention in front view and in a vacuum state.

Figure 2 in cross section illustrates the same device in a front view, but in a vacuum state.

Figure 3 shows an example of the location of the electrodes on the inner helmet when the patient's head is large.

Figure 4 shows an example of the location of the electrodes on the inner helmet when the patient's head is small.

Figure 5 in cross section illustrates the device according to the invention in side view and in a vacuum state.

6 in cross section illustrates the same device in a side view, but in a vacuum state and after fitting to the patient’s head.

The implementation of the invention

The present invention has many fields of application, such as EEG, GEG and MEG, however, further to illustrate the problems solved by the invention, its use in CEG is described in more detail. KEEG is a modification of the EEG, according to which the operator places a certain number (21+) of electrodes on the patient’s head in order to register the electrical activity of the brain. Registration takes place over a period of time and is often presented as a topographic map. Such maps are usually compared with regulatory databases (containing topographic maps). In this regard, it is important that the KEG electrodes are correctly placed in the system, providing an appropriate basis for comparison. Therefore, as a rule, the placement of the electrodes is carried out according to the international system 10-20. The probability of getting the same result in two separate measurements is small; so it is advisable to have a system that is more standardized than the existing ones. You can also apply layouts that differ from the 10-20 system. Figure 1 shows the distance between the electrodes / sensors 1 before pumping out the fluid from the middle layer 2. After pumping out the fluid (see figure 2), the elastic inner helmet 3 is uniformly stretched, and the distance between the electrodes / sensors along the X axis will increase accordingly Figures 3 and 4 show the distances between the electrodes / sensors along the X and Y axes for cases when the head of the patient using the helmet has a correspondingly large or small size. In particular, FIG. 3 corresponds to the head of an adult having a size of 58, and FIG. 4 to the head of a child having a size of 42. In this embodiment, the electrodes will be in the correct positions regardless of the size of the head of the patient using the device / helmet.

Figures 5 and 6 show one particular embodiment. In this case, a type of helmet is illustrated comprising a rigid outer shell 4 and an elastic inner helmet 3, which are connected to each other by a seam 10 that is impermeable to the fluid. It is preferable to design the seam 10 so that the elastic helmet can be attached and disconnected, thereby facilitating the cleaning and repair of the electrodes / sensors 5, change the type of helmet 3, etc. The electrodes / sensors 5 passing through it are fixed on the elastic helmet 3, moreover, a seam that is impermeable to the fluid is used for such fastening, and the wires 8 coming from each electrode / sensor are led out through the seam 6 that is impervious to the fluid and connected to the measuring unit 11 EEG. The pressure of the fluid is regulated by a vacuum pump 7 connected through an outer rigid shell 4 by means of a valve 9. In this embodiment, the fluid used in the middle layer is air. In order for the elastic inner helmet 3 to expand uniformly and unhindered, it is directly attached to the rigid outer shell 4 only along its perimeter by means of a seam 10.

The material used in the helmet 3 may be any suitable flexible material that is impervious to the fluid. Such materials include various modifications of natural or synthetic rubbers and elastomers. More specifically, it may be, for example, latex or neoprene. It is possible for a helmet to have an adjustable number of points for attaching sensors / electrodes 5. The number of sensors / electrodes and their location will depend on the type of method used to measure using this device.

The material for the outer shell 4 of helmet 3 may be any suitable rigid material, including various types of plastic, fiberglass, metal, ceramic, and other similar materials, as well as fiber-reinforced plastic materials.

The material used in layer 2, i.e. between the outer shell 4 and the inner helmet 3, is a fluid, such as air, water or oil, possibly combined with any suitable material that has the ability to uniformly compress / expand depending on the pressure of the fluid. Such materials include, for example, foam, polymer, foam rubber or sponge.

It is possible to change the number of sensors / electrodes in the range from 1 to 256, depending on which method is used. In Fig.1-2 and 5-6, the number of electrodes falling into the presented sections corresponds to a helmet containing 128 electrodes.

In EEG measurements, in addition to the electrodes mentioned above, two reference (ground) electrodes are used, which are independent of the set of electrodes built into the helmet, and are attached to the ears by means of a copper clip and a gel. These additional electrodes can also be mounted in a helmet. The reference electrodes play an important role and are used in all CEEG installations. However, since they are attached to the earlobe or to the mastoid process (directly behind the ear), there is no need to optimize their position using this system.

Electrodes / sensors can be of any type used to measure signals in the brain. When used in medical / neurophysiological diagnostics and treatment courses, electrodes with a liquid medium are preferred since they provide the best signal. Electrodes of this type are used in combination with gel / paste / liquid to obtain improved contact with the scalp. In other applications where signal quality requirements are not so high, dry electrodes can also be used. In many cases, they are preferred because cheaper and more convenient to use.

In the illustrated embodiment, wires 8 coming from the electrodes are brought out through the outer sheath. In other embodiments, it is possible to bundle these wires and attach them to a transceiver mounted on or inside the helmet / outer shell. Then the signals can be transmitted to the outdoor receiver wirelessly.

The present invention will improve the reproducibility of the results of EEG measurements, which will allow these or other (GEG and MEG) measurements to be carried out faster due to the simplified adaptation of the electrodes / sensors in place and there is no need to have helmets with sensors / electrodes made in different sizes. In addition to the above, the invention facilitates the use, for example, of EEG measurements in activities such as controlling and controlling aircraft, robots, computer programs and games, and other devices using brain-computer interaction.

The formation of the seam 10 can be carried out by any suitable means, impervious to the fluid, such as, for example, gluing, welding, clamps, zipper or other clamps and locks.

It is also possible to equip the helmet with a belt to support the chin, further stabilizing the position of the helmet on the head. To obtain the same effect, you can use other technical solutions, such as temples, headphones or other similar devices.

Claims (12)

1. A device for positioning and fixing sensors on the scalp of a patient, comprising an outer layer (4) attached to the inner layer (3), from which it is partially separated by the middle layer (2), the outer layer (4) consisting of a rigid material, impervious to fluid
characterized in that:
the inner layer (3) is made of an elastic material that is impervious to the fluid and having sections for accommodating sensors or electrodes, and is directly attached to the outer layer (4) around its perimeter,
and the middle layer (2) contains a fluid and is configured to pump out fluid from it to uniformly stretch the inner layer, increase the distance between the electrodes and place them regardless of the size of the patient’s head,
wherein the device comprises means for regulating the pressure of the fluid in the middle layer (2). 2. The device according to p. 1, characterized in that it contains many electrodes or sensors attached to the inner layer (3). 3. The device according to p. 1, characterized in that the areas for placing sensors or electrodes correspond to the system 10-20. 4. The device according to claim 1, characterized in that the electrodes are selected for use in electroencephalography (EEG), magnetoencephalography (MEG) or hemoencephalography (GEG). 5. The device according to claim 1, characterized in that the inner layer (3) is made of natural or synthetic rubber, preferably latex or neoprene. 6. The device according to claim 1, characterized in that the fluid in the middle layer (2) is air. 7. The device according to claim 1, characterized in that the means for regulating the pressure is a valve (9). 8. The device according to any one of paragraphs. 1-7, characterized in that it contains means for removing fluid from the middle layer (2), while this tool is preferably a vacuum pump. 9. The device according to claim 7, characterized in that the valve (9) for regulating the pressure is mounted in a vacuum pump (7). 10. The device according to p. 4, characterized in that the electrodes are selected with the possibility of application in the EEG. 11. The use of the device made according to p. 10 for recording EEG, while the fluid is removed from the middle layer of the device, creating a pressure in the middle layer that is lower than the ambient pressure, to uniformly stretch the inner layer and increase the distance between the electrodes,
install the device on the patient’s head,
they let fluid into the middle layer (2), thereby providing pressure to the electrodes from the side of the inner layer (3) directed towards the scalp, and attach the electrodes to the transceiver. 12. A method of placing electrodes on the scalp of a patient, comprising
the use of a device for positioning and fixing sensors on the patient’s scalp according to claim 1, from which the fluid is removed from the middle layer (2), creating a pressure in the middle layer that is lower than the ambient pressure to uniformly stretch the inner layer and increase the distance between the electrodes,
install said device on a patient’s head
and letting fluid into the middle layer (2), thereby providing pressure to the electrodes / sensors from the side of the inner layer (3) directed towards the scalp.

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